One vertex per element, one color per generator, with an edge from x to x·s.
(3,7)(5,8)(9,10)(11,13)(12,17)(14,22)(15,16)(18,23)(19,24)(20,21)(26,32)(27,37)(28,30)(35,40) involution — undirected(1,2,4,6)(3,5,7,8)(9,11,15,12)(10,13,16,17)(14,20,23,19)(18,24,22,21)(25,26)(27,38)(28,34)(29,40)(30,36)(31,32)(33,37)(35,39)(1,3)(2,5)(4,7)(6,8)(10,16)(11,12)(18,22)(19,20)(25,27)(26,33)(28,29)(30,39)(31,37)(32,38)(34,35)(36,40) involution — undirected(9,12,15,11)(10,17,16,13)(14,20,23,19)(18,24,22,21)(25,28,31,30)(26,34,32,36)(27,29,37,39)(33,35,38,40)(1,2)(3,5)(4,6)(7,8)(9,13,15,17)(10,12,16,11)(14,21,23,24)(18,20,22,19)(25,29,31,39)(26,35,32,40)(27,28,37,30)(33,34,38,36)(1,3)(2,5)(4,7)(6,8)(9,14)(10,18)(11,19)(12,20)(13,21)(15,23)(16,22)(17,24)(25,30,31,28)(26,36,32,34)(27,39,37,29)(33,40,38,35)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.